1. Field of the Invention
The invention relates to a mitering gauge for cutting miters particularly on pipe insulating shells which consist of mineral fibers and comprising a console and at least one upright side member having an oblique end face to guide a cutting tool.
2. Discussion of the Background
A mitering gauge for cutting miters on pipe insulating shells is already known from German Utility Model Reference No. 83 13 384. It consists of a U-shaped body on the side members of which there are aligned cut-outs. The cut-outs provided are of a V-shape, the sloping edges forming an angle of 45.degree., 22.5.degree. C., 15.degree. or 11.5.degree. with the perpendicular to the end edge of the side member. The side members of the U-shaped body are in this case bolted to the console by means of wing nuts.
Although this mitering gauge can be dismantled into three component parts, so reducing the space required during transport, its component parts are nevertheless relatively large and therefore cumbersome. In addition, the individual parts are of solid construction and are thus relatively heavy. Finally, the multiplicity of envisaged V-shaped cutouts is not needed for the normal fitting of pipe insulating shells on heating pipes for example. Consequently, they are an unnecessary burden.
When such a mitering gauge is used, the procedure is to place the pipe insulating shell on the console of the gauge, between the side members, whereupon a cutting knife is used to make suitable cut-outs in the pipe insulating shell, corresponding to the cut-outs in the mitering gauge. To do so, the cutting knife is placed on the obliquely extending edges of the V-shaped cut-outs and guided against these edges while the cuts are being made. It has however been found that in the case of mitering gauges which have relatively thin lateral side members, there is a danger of the cutting knife cutting into the obliquely extending edges. This means that the edges can no longer perform their function of perfectly guiding the cutting blade, so that the mitering gauge as a whole becomes unusuable. A widening of the said edges, or guide surfaces, in order to avoid an unintentional cutting into them does however entail an increase in the overall weight of the mitering gauge, so that its ease of handling once again suffers. Last but not least, more material also means increased costs. Finally, in the case of such a mitering gauge, relatively small diameter pipe insulating shells are not satisfactorily guided because the distance between the side members is fixed.